1. Field of the Invention
The present invention relates to data communication apparatus and method for effectively communicating image data.
2. Related Background Art
Conventionally, in image communication to transmit and receive image information between terminals, especially, when it aims to transmit the image information to a specified individual, a facsimile apparatus for transmitting and receiving the image information based on a dedicated protocol by using mainly a public line, a method for adding an image file to an electronic mail transmitted between computer terminals connected to a network, or the like has been utilized.
Further, although it does not aim to transmit the image information to the specified individual, a WWW (World Wide Web) system utilizing a computer communication network becomes noticeable since an internet has been popularized. Like an internet application such as the electronic mail or the like, such the WWW system is a client/server system based on a communication protocol called a TCP/IP (Transmission Control Protocol/Internet Protocol). Further, such the WWW system has been developed as an information retrieval/provision system which can be realized by communicating not only the image information but also data such as text data, voice data, animation data and the like handled in a computer, between a client application having a GUI (Graphical User Interface) called a WWW browser and a WWW server application.
However, in case of utilizing the image communication performed by the above conventional facsimile apparatus, a reception side can not confirm or know what kind of image was transmitted until the transmitted image is actually printed. For this reason, there has been a problem that, even if the transmitted image is unnecessary information for the reception side, an operator at the reception side can not previously confirm contents of such the information to cancel unnecessary reception. Further, the facsimile apparatus tends to be utilized in common by plural operators, there is a premise that the image is transmitted between the two facsimile apparatuses, and the image is transmitted based on one-sided intention of the operator at the transmitter-side facsimile apparatus. Therefore, there have been problems that it is not assured that the transmitted image certainly reaches the operator (individual) at an intended destination, and also there is some fear that contents of the transmitted image are seen by a person other than the operator at the destination. Furthermore, when the operator at the transmission side aims to cause the operator at the destination to confirm necessity or unnecessity of the transmitted image, there has been inconvenience that the operator at the transmitter side must utilize other means, e.g., a telephone or the like, for such confirmation.
On the other hand, in such the conventional method as the image file is added to the electronic mail transmitted between the computer terminals connected to the network, since the electronic mail essentially intended for the individual is utilized, it is possible to solve the above-described problem by securing certainty that the image is transmitted to the operator at the destination. However, like the case where the facsimile apparatus is used, if the communication is not completed, the operator on the reception side can not confirm the received image. Therefore, there has been a problem that, even if the transmitted information is unnecessary for the reception side, the operator on the reception side can not previously confirm it and thus can not previously avoid receiving it. Further, since the electronic mail essentially aims to transmit and receive text data, if such the high-resolution and high-quality image file as used in the printing is added to the electronic mail, the data of which amount is significantly large must be transmitted, thereby seriously loading an electronic mail server. Furthermore, in order to display such the image file on a display device of the reception terminal, there has been a problem that a display application software is necessary, and a large-capacity memory is also necessary, thereby seriously loading a CPU.